Hearing protectors are used largely in the industry to protect the worker from environmental noise. Typically, hearing protectors comprise two ear cups positioned over the wearer's ears. The hearing protectors may either be conventional hearing protectors or active noise cancelling hearing protectors. Active noise cancelling hearing protectors are sometimes provided with active elements, such that the passive sound-reducing function is combined with the function of actively reproducing sound inside the ear cup to allow the user to hear this reproduced sound. Such an active element typically includes an electronic unit comprising a speaker and/or one or a plurality of microphones. The active element may incorporate different functions. One type may, for instance, contain a radio receiver and the electronic circuitry required to reproduce sound received by the radio receiver through the speaker. Another type may be designed such that it is capable of reproducing ambient sound from the vicinity of the hearing protector in anti-phase. Still another type may be designed for communication, such as connection by Bluetooth and/or radio link and/or cable, either built into the device or connected to one or a plurality of external units.
The efficient available means for minimizing the exposure to sounds may however result in that the hearing protector user is unable to be aware of the surroundings both audibly and, when the user performs various task demanding full attention, visibly. Thus, various measurements have been taken in the art to provide means to notify a hearing protector user of important events.
US 2008/189820 A1 discloses a protection mask for welding comprising speakers configured to alert the user if a gas leak has been identified in the vicinity or inform the wearer regarding parameters concerning the welding equipment or operation.
EP 1674062 A1 discloses a hearing protector comprising an evaluation unit and a microphone. Specific sound patterns can be loaded into the hearing protector via a wired or wireless interface. When a sound corresponding to a registered sound pattern occurs the hearing protector user is alerted by a speaker in the hearing protector. The alert may comprise of synthetic speech, a predefined sound or a reproduction of the sound pattern in question.
US 2015/0190284 A1 discloses an ear plug with active noise cancellation means comprising a microphone and a unit storing two databases. The first database comprises sounds which should be let through to the ear plug user and the second database comprises sounds which should be eliminated by the active noise cancelling function. The ear plug user can record and allocate new sounds to the databases through buttons on the ear plug. The earplug further comprises a speaker for modifying, enhancing or generating a desired sound to the ear plug user.